Overview
The Parallel Printer Card (Model PIOC) is a
The PIOC can have up to 12 digital TTL compatible outputs and up to 17 digital TTL compatible inputs. 12 of these inputs and outputs share connector pins so you cannot have 12 inputs and 17 outputs at the same time. The input/output lines are available through a female
To understand how the PIOC can be used you must first understand how the IBM PC parallel port works from inside the computer. Each parallel port has one main port address for outputting data, the Base Register. The next two addresses above that address are used for handshaking control. The first address is the Status Register, and the second address is the Control Register. For instance, on a typical computer LPT1 might be located at hexadecimal address 378h, which is the Base Register. The Status Register will be located at 379h and the Control Register will be located at 37Ah. Table 1 shows the functions of each pin on the DB- 25 connector when the PIOC is connected to a printer.
Documentation Number PIOC2595 Manual | 1 |
